Machine lighting



March 1956 J. B. STRACHAN, JR

MACHINE LIGHTING Filed May 14, 1952 IN VEN TOR.

mm Mm m C 79 W 5 B.

United States Patent -MACH1NE LIGHTING John B, Strachan, Jr., Euclid, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio Application May 14, 1952,-Seria'l No. 287,669

1 Claim. (Cl. 240*2) In machines in which there is relative movement between a tool and a work-piece, as by a reciprocable member, the customary overhead lighting arrangement is not satisfactory. Some positions of the movable member occasion shadows; and in some instances when the machine operator must bend over the work for close inspection, the difficulties from such additional shadow are serious. In efforts to avoid these conditions it has been proposed to mount a light on the machine frame as near to the moving part as practicable. Such expedients however have not been satisfactory, as there still is a tendency for shadows to occur in some positions of the movable member. If a light were mounted on the movable member and with a conductor cord long enough to accommodate its range of movement, a loop of slack cord would be in the way and would furthermore be prohibitive on account of short-circuiting hazard. It is highly important that the lighting for machining opera tions should be as close as possible, and also constant in its distribution regardless of the position of the movable member. By the present invention, this long-desired result is attained, and by an arrangement which .is compact and in compliance with safety requirements as regards short-circuiting and fire hazards. Other objects and advantages will appear from the following description.

To the accomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the claim, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is a perspective view of a machine embodying a lighting arrangement in accordance with the invention;

Fig. 2 is a fragmentary similar view of the corresponding portion of the machine, showing a modified arrangement;

Fig. 3 is a perspective view of the machine-side of the conductor cord takeup member centrally broken out, and on larger scale; and

Fig. 4 is an enlarged scale transverse section of the conductor cord taken on a plane substantialy indicated by line IV-IV, Fig. 2.

Referring more particularly to Fig. 1, there is shown a lathe, generally illustrative of all machines here contemplated, in which there is a movable member or carriage for which localized efiicient light is desired. Thus, the machine illustrated shows a bed 2 with a movable carriage 3 reciprocably slidable through the range of the length of the bed. Head-stock mechanism 4 with housing 5 for driving mechanism, and tail stock 6 comprise the further parts as conventionally involved. On the back edge of the carriage 3 a bracket or light-support arm 7 is secured so as to travel with the carriage. Such light-support arm has a reflector 8 and a lamp bulb 9 in a position directly {over the line of work. Preferably the light-support arm 7 has a hollow passageway for the conductor to the lamp, and from the lower end of "the light-support arm a flexible conductor 10 extends to mean such as to maintain the conductor cord 10 taut at all'ti'm'es as the cord is-drawn out by the movement of the carriage, or is wound back by the reel as the carriage approaches. Thus, one arrangement involves a reel-spool with flanges 11a, the conductor cor-d being wound on the body or barrel 11b therebetween, the whole being mountedon a spindle 13 projecting from the rear face of the bed, and removal of the reel therefrom being prevented by a suitable nut on the free end of the spindle. Within the barrel 11b a coil spring 14 is secured by its inner end to the fixed spindle 13 and at its outer end to the inside of the hollow barrel 11b. With this, it is seen that the coil spring tends to turn the reel in wind-up of the cord, and its strength is such that the cord easily pays out or in as the varying movement of the carriage 3 occasions. Smooth winding of the cord on the reel is assured by suitable means; for instance a traverse guide 15 pivoted at its lower end 16 to a lug projecting from the bed 2, the guide thence at its intermediate portion having a short projecting arm carrying a small roller 17 which rides in a back and forth cam groove 18 in the hub 18 on the reel flange 11a. At its free end the traverse guide 15 has rollers 19 between which the conductor cord 10 is threaded on its way to be drawn down onto the reel.

In some instances, less desirably, instead of the reel takeup as in Fig. l, the conductor cord 10', Fig. 2, is inthe form of a composite helical coil of a coil spring 20, Fig. 4, and a dual conductor 21 suitably insulated, and the assembly of coil spring and conductor being encased by a covering 22, braided or otherwise, which allows sufficient flexibility for the helical coil to greatly change its length in expansion or contraction as the carriage 3 moves back and forth. Such expansion card 10' extends between the bottom outlet of the light support 7 and a connection box 23 which is secured to the back face of the machine, and which receives a feed-in lead 12' for the current supply.

The lamp 9 has its current supply from a transformer 24, which feeds to the connection box 23 and which together with the leads 25 to the machine drive motor in the head-stock housing 5, is controlled by an on and off switch 26 in common on the line. Thus, the drive motor can have a higher voltage than is suitable for the lamp, and the lamp 9 not only illuminates the work, but also performs an additional function of being a tell-tale which indicates when the motor is on or ofi.

Irrespective of the particular detail and character of the machine, the feature in all cases is the lamp mounted directly on the traveling carriage, and provided with a conductor whose practical length is suited to the position of the traveling carriage at any given instance and is continually maintained taut.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

In a machine including a stationary frame and a powerdriven carriage movably supported thereby; means for providing predetermined illumination in the region of said carriage in all positions and travel of the same, said means comprising an upwardly extending support secured to the carriage for movement therewith in fixed relation, an electric lamp mounted on said support above the carriage, an electric current outlet afiixecl to the stationary frame of the machine, a reel having a shaft mounted for rotation on said frame, a conductor cord extending from said out let to said lamp with an intermediate slack portion wound about said reel, spring means exerting wind-up tensioning on the reel thereby to maintain the cord taut between the reel and the lamp support in travel of the latter with the carriage, a guide for directing the conductor cord to and from the reel in winding and unwinding of the same, said guide being supported for movement adjacent to and transversely of the reel, a cam surface formed on the reel shaft, and a co-operable cam element carried by said guide, said cam surface and cam element cooperating upon rotation of the reel to cause the guide to move back 4 and forth relative to the reel face and thus provide uniform laying-on of the convolutions in winding of the cord.

References Cited in the file of this patent UNITED STATES PATENTS 666,513 Gerhardt Ian. 22, 19.01

743,270 Golcher Nov. 3, 1903 1,175,274 Klorer Mar. 14, 1916 1,247,672 Hallberg Nov. 27, 1917 1,978,734 Apple et al. Oct. 30, 1934 2,201,954 Flygare May 21, 1940 2,603,431 Cramer July 15, 1952 2,624,831 Father Jan. 6, 1953 FOREIGN PATENTS 60,227 Germany May 24, 1891 

